Blue-violet Light Research Articles

Efficacy of violet–blue light to inactive microbial growth

The increase in health care-associated infections and antibiotic resistance has led to a growing interest in the search for innovative technologies to solve these problems. In recent years, the interest of the scientific community has focused on violet–blue light at 405 nm (VBL405). This study aimed to assess the VBL405 efficiency in reducing microbial growth on surfaces and air. This descriptive study run between July and October 2020. Petri dishes were contaminated with P. aeruginosa, E. coli, S. aureus, S. typhimurium, K. pneumoniae and were placed at 2 and 3 m from a LED light source having a wavelength peak at 405 nm and an irradiance respectively of 967 and 497 µW/cm2. Simultaneously, the air in the room was sampled for 5 days with two air samplers (SAS) before and after the exposition to the VBL405 source. The highest microbial reduction was reached 2 m directly under the light source: S. typhimurium (2.93 log10), K. pneumoniae (2.30 log10), S. aureus (3.98 log10), E. coli (3.83 log10), P. aeruginosa (3.86 log10). At a distance of 3 m from the light source, the greatest reduction was observed for S. aureus (3.49 log10), and P. aeruginosa (3.80 log10). An average percent microbial reduction of about 70% was found in the sampled air after 12 h of exposure to VBL405. VBL405 has proven to contrast microbial growth on the plates. Implementing this technology in the environment to provide continuous disinfection and to control microbial presence, even in the presence of people, may be an innovative solution.

Green synthesis of blue-green photoluminescent β-SiC nanowires with core-shell structure using coconut shell as carbon source

This work proposes a green method for synthesizing SiC nanowires (NWs) via the chemical vapor deposition (CVD) technique using coconut shell and silicon as raw materials. Using coconut shell as carbon source decreases the synthesis temperature of SiC. A large number of core-shell SiC NWs were obtained after firing at 1200 °C, a thin SiO2 layer is distributed on the outer shell of SiC NWs. The synthesized SiC NWs grow along the [111] direction, up to dozens of micrometers in length and diameters of 10–75 nm. However, the chain-bead structure of SiC NWs is formed after firing at 1400 °C due to the SiO2 bead embedded in SiC NWs. The synthesized core-shell SiC NWs fired at 1200 °C emit strong violet-blue light, which has good application prospects in optoelectronic devices.

Exploiting Violet-Blue Light to Kill Campylobacter jejuni: Analysis of Global Responses, Modeling of Transcription Factor Activities, and Identification of Protein Targets.

ABSTRACTCampylobacter jejuni is a microaerophilic foodborne zoonotic pathogen of worldwide concern as the leading cause of bacterial gastroenteritis. Many strains are increasingly antibiotic resistant and new methods of control are required to reduce food-chain contamination. One possibility is photodynamic inactivation (PDI) using violet-blue (VB) light, to which C. jejuni is highly susceptible. Here, we show that flavin and protoporphyrin IX are major endogenous photosensitizers and that exposure of cells to VB light increases intracellular reactive oxygen species (ROS) to high levels, as indicated by a dichlorodihydrofluorescein reporter. Unusually for an oxygen-respiring bacterium, C. jejuni employs several ROS-sensitive iron-sulfur cluster enzymes in central metabolic pathways; we show that VB light causes rapid inactivation of both pyruvate and 2-oxoglutarate oxidoreductases, thus interrupting the citric acid cycle. Cells exposed to VB light also lose heme from c-type cytochromes, restricting electron transport, likely due to irreversible oxidation of heme-ligating cysteine residues. Evaluation of global gene expression changes by RNAseq and probabilistic modeling showed a two-stage protein damage/oxidative stress response to VB light, driven by specific regulators, including HspR, PerR, Fur, and RacR. Deletion mutant analysis showed that superoxide dismutase and the cytochrome CccA were particularly important for VB light survival and that abolishing repression of chaperones and oxidative stress resistance genes by HcrA, HspR, or PerR increased tolerance to VB light. Our results explain the high innate sensitivity of C. jejuni to VB light and provide new insights that may be helpful in exploiting PDI for novel food-chain interventions to control this pathogen.IMPORTANCE Campylobacteriosis caused by C. jejuni is one of the most widespread zoonotic enteric diseases worldwide and represents an enormous human health and economic burden, compounded by the emergence of antibiotic-resistant strains. New interventions are urgently needed to reduce food-chain contamination. Although UV light is well known to be bactericidal, it is highly mutagenic and problematic for continuous exposure in food production facilities; in contrast, narrow spectrum violet-blue (VB) light is much safer. We confirmed that C. jejuni is highly susceptible to VB light and then identified some of the global regulatory networks involved in responding to photo-oxidative damage. The identification of damaged cellular components underpins efforts to develop commercial applications of VB light-based technologies.

Synthesis, Structures, optical properties and DFT studies of neodymium complexes containing octanoyl amino carboxylic acids

Amino acid rare-earth complexes are widely used due to their unique physical and chemical properties. In this study, three kinds of neodymium (III) complexes with octanoyl-aminocarboxylate ligands (abbr. Nd(oct-ala)3, Nd(oct-phe)3, Nd(oct-ser)3) were prepared by a chemical reaction method in methanol as the solvent. The chemical formulas and coordination modes of the neodymium complexes were determined by elemental analysis, 1H NMR and FT-IR. Additional analyses by X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the neodymium complexes have lamellar irregular shapes and long-range disordered amorphous structures. The thermal performance of the complexes was determined by differential scanning calorimetry (DSC) and thermal gravimetry-differential thermal analysis (TG-DTA). Nd(oct-phe)3 and Nd(oct-ser)3 appeared glassy when heated. The solubility of the complexes in various organic reagents was also measured. The optical properties of the complexes were examined using UV–Vis absorption, polarizing microscopy observations, fluorescence spectra, quantum yield, and fluorescence lifetime. The luminescence properties of the complexes as a function of temperature were further observed by analysis of temperature-dependent emission spectra. The polarizing microscopy observations show that the three neodymium complexes exhibited the characteristic properties of thermotropic liquid crystals. UV–Vis, fluorescence spectroscopy, and quantum yield results show that they have excellent light absorption and luminescence properties. Temperature-dependent emission spectra show that the complexes have good luminescence properties in the temperature range of 25–160 °C. The powdered complexes and the complexed solutions in methanol were irradiated with 380 nm UV light, resulting in blue-violet light emission. A warm white-light device was constructed to further verify the luminescence of the complexes after combining with three kinds of rare-earth complexes (Nd(oct-phe)3, Eu(oct-phe)3, and Tb(oct-phe)3. The color rendering index (CRI) and color temperature (CCT) were measured. In addition, the density functional theory (DFT) was used to determine the geometric structures (Fig S1), and obtain 1H NMR, FT-IR spectra of the neodymium complexes (Fig S2, S3). Their structures were further examined by comparing the calculated with the experimental spectra. The results show that the ligands coordinate to the central Nd3+ through the bidentate chelation mode.

Visible 405 nm Violet-Blue Light Successfully Inactivates HIV-1 in Human Plasma.

Despite significant advances in ensuring the safety of the blood supply, there is continued risk of transfusion transmitted infections (TTIs) from newly emerging or re-emerging infections. Globally, several pathogen reduction technologies (PRTs) for blood safety have been in development as an alternative to traditional treatment methods. Despite broad spectrum antimicrobial efficacy, some of the approved ultraviolet (UV) light-based PRTs, understandably due to UV light-associated toxicities, fall short in preserving the full functional spectrum of the treated blood components. As a safer alternative to the UV-based microbicidal technologies, investigations into the use of violet-blue light in the region of 405 nm have been on the rise as these wavelengths do not impair the treated product at doses that demonstrate microbicidal activity. Recently, we have demonstrated that a 405 nm violet-blue light dose of 270 J/cm2 was sufficient for reducing bacteria and the parasite in plasma and platelets suspended in plasma while preserving the quality of the treated blood product stored for transfusion. Drawn from the previous experience, here we evaluated the virucidal potential of 405 nm violet-blue light dose of 270 J/cm2 on an important blood-borne enveloped virus, the human immunodeficiency virus 1 (HIV-1), in human plasma. Both test plasma (HIV-1 spiked and treated with various doses of 405 nm light) and control plasma (HIV-1 spiked, but not treated with the light) samples were cultured with HIV-1 permissive H9 cell line for up to 21 days to estimate the viral titers. Quantitative HIV-1 p24 antigen (HIV-1 p24) levels reflective of HIV-1 titers were measured for each light dose to assess virus infectivity. Our results demonstrate that a 405 nm light dose of 270 J/cm2 is also capable of 4–5 log HIV-1 reduction in plasma under the conditions tested. Overall, this study provides the first proof-of-concept that 405 nm violet-blue light successfully inactivates HIV-1 present in human plasma, thereby demonstrating its potential towards being an effective PRT for this blood component safety.

Spectrum Acquisition System Using Photoelectric Detection and Its Data Mining Simulation of Spectral Texture Features

Weak spectral signal detection technology is a new subject in the measurement engineering field. It obtains the characteristic information of the measured object based on the characteristics of light diffraction, interference, polarization and so on. Regarding light source entropy, the artificial light source of mercury argon lamp with a spectrum of 250 nm~918 nm is selected as the first research object. The grating monochromator with built-in grating scale lines (1200 g/mm, 600 g/mm) is selected as the light splitting device. Due to the weak spectral signal, the output signal is vulnerable to noise interference after a certain amount of photoelectric conversion. AD202 variable voltage coupling filtering technology is adopted. It means that in the signal isolation and amplification process, the AD202 variable voltage coupled filter amplifier chip is employed to design the current/voltage conversion circuit and the same direction proportional operation amplifier circuit. Meanwhile, a second-order low-pass filter circuit is designed based on the characteristics of the OP07 operational amplifier. For the data mining of multispectral image texture features, Contourlet transform is used, that is, the multispectral image texture features are fuzzy preprocessed to remove the adjacent range correlation knowledge. On this basis, the texture features of multispectral images are analyzed. In the experiment, Contourlet transform is adopted to transform multispectral images from spatial domain to frequency domain, which has the advantages of short extraction time, low cost, and high mining accuracy. A spectrum acquisition system based on photoelectric detection is designed. With chlorophyll as the research object, the sample solution to be tested has high photoelectric absorbance in the range of blue-violet light (400 nm~500 nm) and red-orange light (600 nm~700 nm).

Carbon Nitride with Rationally Designed π-Conjugated Structure for Bright Blue-Violet Light-Emitting Diodes.

Carbon nitride consisting of the broken π-conjugated structure (bc-CN) is designed as the emitting layer in a blue-violet light emitting diode (LED). The bc-CN is prepared by a metal-oxide (MgO) template-assisted method, in which the low reaction temperature and nano MgO jointly control the degree of polymerization to form cyano groups and broken π-conjugation in the bc-CN nanosheets (bc-CN NS) which emit intense blue-violet photoluminescence at 412nm. The broken π-conjugated heptazine-ring structure in the bc-CN NS mitigates non-radiation energy loss and promotes the d*-LP transition. As a result, a high quantum efficiency of 73.1% is achieved. The excellent dispersing ability of the bc-CN NS enables solution-based fabrication of the light emitting diode (LED). The LED exhibits intense electroluminescence of 236cd m-2 at 412nm with an external quantum efficiency of 0.46%. The broken π-conjugation modulates the optical properties of the polymerized carbon nitride semiconductor giving rise to intense blue-violet electroluminescence, which is very desirable for printable and wide-color-gamut display devices.

Simple Approach to Mitigate the Emission Wavelength Instability of III-Nitride μLED Arrays.

III-nitride semiconductors and their heterojunctions exhibit intrinsic polarization due to the asymmetry of their wurtzite structure, which determines all the fundamental properties of III-nitride optoelectronics. The intrinsic polarization-induced quantum-confined Stark effect leads to an emission wavelength shift with increasing injection current for III-nitride visible LEDs, forming an insurmountable barrier for the fabrication of a full color display. For instance, a yellow LED designed to produce yellow light emits green or blue light at an elevated current, while a green (blue) LED gives off blue (violet) light with increasing current. This color instability becomes a serious issue for a microdisplay such as the displays for augmented reality (AR)/virtual reality (VR) typically utilized at proximity to the eye, where human eyes are sensitive to a tiny change in light color. It is well-known that an optical mode wavelength for a microcavity is insensitive to injection current. In this work, we have demonstrated an approach to epitaxially integrating microLEDs (green microLEDs as an example, one of the key components for a full color microdisplay) and a microcavity. This allows the emission from the microLEDs to be coupled with the microcavity, leading to a negligible emission wavelength shift with increasing injection current. In contrast, identical microLEDs but without a microcavity show a large emission wavelength shift from 560 nm down to 510 nm, measured under identical conditions. This approach provides a simple solution to resolving the 30-year issue in the field of III-nitride optoelectronics.

Preparation of polydopamine-coated TiO2 composites for photocatalytic removal of gaseous ammonia under 405 nm violet-blue light

Preparation of polydopamine-coated TiO2 composites for photocatalytic removal of gaseous ammonia under 405 nm violet-blue light

A study of the effect of reactive oxygen species induced by violet and blue light from oxytetracycline on the deactivation of Escherichia coli

Oxytetracycline (OTC), a tetracycline antibiotic, is a broad-spectrum antibacterial agent. In this investigation, liquid chromatography–mass spectrometry (LC–MS) is utilized to determine the effects of blue light (λ = 448 nm) illumination (BLIA) and violet light (λ = 403 nm) illumination (VLIA) on conformational changes in OTC at pH 7.8. The photochemical effect of OTC that is exposed to BLIA and VLIA on the deactivation of Escherichia coli (E. coli) is studied. The deactivation of E. coli has an insignificant effect on treatment with OTC alone. OTC is relatively unstable under BLIA and VLIA illumination in an alkaline solution, and OTC has been shown to inactivate E. coli by generating reactive oxygen species (ROS). Less anionic superoxide radicals (O2•−) are generated from OTC that is treated with BLIA than that from VLIA treatment, so OTC is more efficient in inactivating E. coli under VLIA. Inactivation of reduction rates of 0.51 and 3.65 logs in E. coli are achieved using 0.1 mM OTC under BLIA for 120 min and VLIA for 30 min, respectively, under the same illumination intensity (20 W/m2). Two photolytic products of OTC (PPOs) are produced when OTC is exposed to BLIA and VLIA, with molecular ions at m/z 447 and 431, molecular formulae C21H22N2O9 and C21H22N2O8, and masses of 446.44 and 430.44 g/mol, respectively. The results show that when exposed to VLIA, OTC exhibits enhanced inactivation of E. coli, suggesting that the photochemical treatment of OTC is a potential supplement in a hygienic process.

Antibacterial Action of Visible 405-nm light for Bacterial Reduction in Blood Plasma

The introduction of risk prevention measures, such as blood screening and donor deferrals have dramatically reduced the incidence of transfusion-transmitted viral infections. Nevertheless, bacterial contamination of blood transfusion products remains a concern to patient health, and a range of pathogen reduction technologies have been developed to reduce this risk. Visible violet-blue light, in the region of 405-nm, has recently demonstrated potential for in situ treatment of ex vivo stored plasma and platelet products, without the need for additional photosensitizers. This study assessed the broad-spectrum efficacy of 405-nm light against a range of bacteria implicated in transfusion-transmitted infections: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniaeandYersinia enterocolitica. Plasma was seeded with clinically-relevant low-level bacterial contamination (102-103CFUmL-1) and exposed to a 405-nm light dose of 360 Jcm-2 (1-hr at 100mWcm-2) using a small-scale exposure system. Broad spectrum antibacterial efficacy was observed, with 99.0 – 100% inactivation achieved for all bacterial species tested. Bacterial inactivation tests were then scaled-up to expose large volumes of prebagged plasma seeded with S. aureusat ~103 CFUmL-1, to 22mWcm-2 405-nm light, under agitation, (≤396 Jcm-2). Successful bacterial inactivation was observed using the large-scale exposure system, with a dose of 238 Jcm-2 (3-hr at ~22mWcm-2) achieving complete (3.5-log10) reductions in prebagged bacterial-seeded plasma (P=0.001). Results from this study support further development of visible 405-nm light technology as a bactericidal tool for application in transfusion medicine. This abstract reflects the views of the author and should not be construed to represent FDA’s views or policies.

Changes in Greenhouse Grown Tomatoes Metabolite Content Depending on Supplemental Light Quality.

Tomatoes (Solanum lycopersicum L.) are good source of several biologically active compounds and antioxidants, especially lycopene, phenolic compounds, and vitamins. Tomatoes are found all over the world and are cultivated in a wide variety of environmental conditions. Light-emitting diode (LED) lamps are increasingly being used in the cultivation of tomatoes due to their cost-effectiveness and wide range of possibilities to adapt the spectrum of light emitted to the needs of plants. The aim of this study is to evaluate the effect of different additional lighting used in the greenhouse on the accumulation of biologically active compounds in different varieties of tomato fruit. Chemical composition—content of organic acids, lycopene, total carotenoids, total phenolics and flavonoids as well as dry matter, soluble solids content, and taste index were determined in five tomato cultivars (“Bolzano F1,” “Chocomate F1,” “Diamont F1,” “Encore F1,” and “Strabena F1”), which were cultivated in greenhouse in an autumn-spring season by using additional lighting with 16 h photoperiod. Three different lighting sources were used: LED, induction (IND) lamp, and high-pressure sodium lamp (HPSL). Experiments were performed during 3 years. Results showed that tomato varieties react differently to the supplemental lighting used. Cultivars, such as “Encore” and “Strabena,” are the most unresponsive to supplemental light. Experiments have shown that HPSL stimulates the accumulation of primary metabolites in tomato fruit. In all the cases, soluble solids content was 4.7–18.2% higher as compared to other lighting sources. As LED and IND lamps emit about 20% blue-violet light, the results suggest that blue-violet light of the spectrum stimulates the accumulation of phenolic compounds in the fruit by 1.6–47.4% under IND and 10.2–15.6% under LED compared to HPSL. Red fruit varieties tend to synthesize more β-carotene under supplemental LED and IND light. An increase of blue promotes the synthesis of secondary metabolites.

The Effect of The Blue-Violet Light Emitting Diode (Led) Irradiation on the Bleeding and Pain Following Tooth Extraction.

Tooth extraction is one of the most common oral surgeries carried out daily in dental clinics. Bleeding and pain are considered common sequelae after tooth extraction, which are considered a major concern. The purpose of this study was to evaluate the effectiveness of the irradiation on the extraction socket with a blue-violet light-emitting diode (LED) on the hemostasis and the pain.The study was designed as a randomized prospective split-mouth clinical study in which 82 tooth extractions were performed on 31 patients who required bilaterally paired tooth extractions. The side impacted by LED radiation until the bleeding stopped was the study group (left side), whereas the other side where the bleeding stopped without intervention was the control group (right side). The duration of bleeding time was measured and compared. The pain level was assessed postoperatively using the numeric rating scale and total analgesic dosages.Results indicate that in the study group there was a reduction in postextraction bleeding time as compared with the control group. The mean bleeding time was (26.71 seconds) and (291.95 seconds), respectively. It was statistically significant ( P = 0.000). Regarding the effect of LEDs on pain, the result shows no difference in the pain level between the 2 groups, which means LEDs have a nonsignificant effect on pain.The blue-violet LED reduces the bleeding time of the extracted socket after tooth extraction, and prevents postoperative oozing, but has no effect on the reduction of postoperative pain. LED therapy has no side effects.

NIR-Responsive Photodynamic Nanosystem Combined with Antitumor Immune Optogenetics Bacteria for Precise Synergetic Therapy.

Photodynamic therapy (PDT) and immunotherapy are considered promising methods for the treatment of tumors. However, these treatment systems are still suffering from shortcomings such as hypoxia, easy metastasis, and delayed immune response during PDT. Therefore, it is still challenging to establish a programmed and rapid response immune combination therapy platform. Here, we construct a two-step synergetic therapy platform for the treatment of primary tumors and distant tumors using upconversion nanoparticles (UCNPs) and engineered bacteria as therapeutic media. In the first step, erbium ion (Er3+)-doped UCNPs act as a photoswitcher to activate the photosensitizer ZnPc to produce 1O2 for primary tumor therapy. In the second step, thulium ion (Tm3+)-doped UCNPs can emit blue-violet light under the excitation of near-infrared (NIR) light to activate the engineered bacteria to produce interferon (INF-γ) and release them in the intestine, which can not only treat tumors directly but also act with PDT to regulate immune pathways to activate the immune system, resulting in a joint immunotherapy effect to inhibit the growth of distant tumors. As a new type of programmatic combination therapy, we have proved that this platform can jointly activate the body's immune system during PDT and immunization treatment and can effectively inhibit tumor metastasis.

Highly Stable and Efficient Mn2+ Doping Zero-Dimension Cs2ZnxPb1-xCl4 Alloyed Nanorods toward White Electroluminescent Light-Emitting Diodes.

Zero-dimensional (0D) crystal structure perovskite NCs have reemerged as promising materials owing to their superior long-term stability; however, their poor conductivity leads to the inferior electrical performances and critically restricts the optoelectronic application of 0D perovskite materials. Herien, the alloyed 0D crystal structure Cs2ZnxPb1-xCl4 nanorods (NRs) have been synthesized by the modified hot-injection method, which emits bright blue-violet light at 408 nm, and the optimized photoluminescence quantum yield (PLQY) reaches 26%. The Cs2Zn0.88Pb0.12Cl4 NRs display more excellent air stability and an order of magnitude higher conductivity than CsPbCl3 nanocube films. In addition, we dope Mn2+ ions into the Cs2Zn0.88Pb0.12Cl4 NRs, which accomplished the optimized PLQY of 40.3% and polarized emission with r = 0.19. The light-emitting diodes (LEDs) based on Mn2+ ion doped Cs2Zn0.88Pb0.12Cl4 NRs exhibit a chromaticity coordinate (CIE) of (0.36, 0.33), an EQE of 0.3%, and a maximum luminance of 98 cd m-2. This work has enriched ideas for the production of white light perovskite LEDs.

Photoelectric Computer Simulation of Cu2O/WO3 Composite Semiconductor Materials

Cuprous oxide (Cu2O) is a P-type semiconductor material with a narrow forbidden band and shows good optoelectronic performance. Due to the easy composition of photo-induced electrons and holes in Cu2O, the photocatalytic activity is reduced, so it is necessary to reduce the composition of photo-induced electrons and holes in Cu2O to improve its optoelectronic performance. In this work, nano-Cu2O and Cu2O/tungsten trioxide (WO3) composite semiconductor films were first prepared by anodization. Nano-Cu2O/WO3 composite semiconductors can be obtained in both alkaline solution and acidic solution. Among them, the granular Cu2O/WO3 composite film can be obtained by annealing treatment at 370 °C after anodization at 10 V voltage in the alkaline solution, and its photocurrent density is 50 times that of pure Cu2O film. The flaky Cu2O/WO3 composite film can be obtained by annealing treatment at 400 °C after anodization at 0.8 V voltage in the acid solution, and its photocurrent density is 17 times that of pure Cu2O film. The Cu2O/WO3 composite film prepared in the acid solution is taken to peel off the single-layer film by the micromechanical exfoliation method, and to construct the semiconductor optoelectronic device based on single-layer Cu2O/WO3 by photolithography micromachining technology. The nano-film device is irradiated with different wavelengths of laser light, and it is found that Cu2O/WO3 shows excellent photosensitivity. In addition, the current changes greatly under blue-violet light irradiation and changes slightly under red light irradiation. The field effect transistor based on single-layer Cu2O/WO3 is constructed, and its field effect transport performance is affected by the adsorption of water molecules. The results reveal that with the increase of relative humidity, the conductivity and switching voltage of the optoelectronic device increase accordingly.

Frameless Stereotactic Biopsy with Intraoperative Computed Tomography "Assessment of Efficacy and Real Target Registration Error".

Frameless stereotactic brain biopsy (FSB) with navigation system has been widely used. We reported preliminary experience of FSB with intraoperative computed tomography (iCT) and examined the usefulness of this novel adjuvant technique and real target registration error (rTRE) of FSB. The FSB with 5-aminolevulinic acid (5-ALA) and iCT was performed on 10 patients. The gadolinium-enhanced lesions on magnetic resonance image were defined as the biopsy target. In the procedure, iCTs were scanned twice, for autoregistration of the navigation system and for confirmation of the position of the actual inserted biopsy needle. The red fluorescence of the samples was observed under excitation with violet-blue light through a low-cut filter of neurosurgical microscope. The distance between the planned target and the tip of the biopsy needle in the image of iCT was calculated in a workstation for the assessment of rTRE. The median volume of the target was 12.13 mL (0.06-39.15 mL). We performed the surgical procedure in a prone position in four patients. None to faint 5-ALA-induced fluorescence was observed in six samples. There existed no sampling errors. The mean target distance between the planned and real targets of the mean rTRE of FSB was 2.7 ± 0.56 mm. The real TRE of FSB was first reported and was larger than the reported rTRE exactly calculated from the fiducial registration error. iCT guarantees accurate tumor sampling with autoregistration regardless of the surgical position and prevents inaccurate biopsy to occur even with ALA fluorescence assistance.

High-Performance organic photodiodes for Blue-Light hazard detection

In this study we incorporated a PffBT4T-2OD:PC71BM bulk-heterojunction (BHJ) active layer in the layer structure ITO/ZnO/BHJ/MoO3/Ag, obtaining high-performance organic photodiodes (OPDs) for application in blue-light hazard (BLH) detection. The high crystallinity of PffBT4T-2OD resulted in the OPD displaying high performance even when the thickness of the BHJ layer was up to 850 nm. The efficient OPD suppressed charge injection (from the metal contacts), thereby providing state-of-the-art performance: external quantum efficiencies of greater than 70% (380–710 nm), a value of Jd of 1.18 × 10-9 A cm−2 (-2 V), and high detectivity [2.9 × 1013 Jones, −2 V (710 nm)]. The observed ultra-high cut-off frequency [greater than800 kHz (at 530 nm), with rise/fall times of less than 350 ns at reverse biases of less than −3 V] exceeded that of a silicon photodiode and made the system suitable for use in image photosensors and medical monitoring. The wide linear dynamic range (LDR, 530 nm) of the OPD (139 dB at −1 V, from 2.2 × 10-4 to 2.5 × 10-11 A cm−2) encompassed the mesopic and scotopic vision regimes. Combined with the design of a BLH filter, we calculated the environmental BLH weighted irradiation power density [WDBLH = CB × JSC (current density of diode)] to evaluate the BLH effect for various light sources and commercially available lenses; here CB (12.69, reported herein) is a corrective constant for BLH photodetectors. Finally, our design allowed ready determination of the ratio of blue-violet and blue-green light.

Violet-blue Light Induces "Natural" Photodynamic Plasma Disinfection with Endogenous Sensitizers.

Naturally, endogenous porphyrins can provide sensitized disinfection power, and to photobiologists' delight, violet-blue light has potential virtues, but progress is needed before violet-blue light treatment can be used for microbe treatment of blood plasma, and yet safeguard against protein photooxidation. A report by Maclean etal. in this issue of Photochemistry & Photobiology on microbe reduction in blood plasma showing negligible competing protein photooxidation may bring that goal a step closer.

Comparative Efficiency of Lutein and Astaxanthin in the Protection of Human Corneal Epithelial Cells In Vitro from Blue-Violet Light Photo-Oxidative Damage

The aim of this study was to compare in vitro the protective and antioxidant properties of lutein and astaxanthin on human primary corneal epithelial cells (HCE-F). To this purpose, HCE-F cells were irradiated with a blue-violet light lamp (415–420 nm) at different energies (20 to 80 J/cm2). Lutein and astaxanthin (50 to 250 μM) were added to HCE-F right before blue-violet light irradiation at 50 J/cm2. Viability was evaluated by the CKK-8 assay while the production of reactive oxygen species (ROS) by the H2DCF-DA assay. Results have shown that the viability of HCE-F cells decreased at light energies from 20 J/cm2 to 80 J/cm2, while ROS production increased at 50 and 80 J/cm2. The presence of lutein or astaxanthin protected the cells from phototoxicity, with lutein slightly more efficient than astaxanthin also on the blunting of ROS, prevention of apoptotic cell death and modulation of the Nrf-2 pathway. The association of lutein and astaxanthin did not give a significant advantage over the use of lutein alone. Taken together, these results suggest that the association of lutein and astaxanthin might be useful to protect cells of the ocular surface from short (lutein) and longer (astaxanthin) wavelengths, as these are the most damaging radiations hitting the eye from many different LED screens and solar light.